And if one believes it's the will of God for them to stay afflicted then maybe they should stop seeing doctors or taking medicine. I mean why should they try to get out of the will of God?
In the OT, sickness and disease was always punishment due to disobedience and unbelief but that was under the Law
Under the Law, God literally promised Israel that if they obey him, they will never fall sick (Deuteronomy 7:15, Exodus 15:26)
Under the promised kingdom of heaven on Earth, no one in Israel will be maim or sick too (Isaiah 33:24, Psalms 103:1-5.
Israel broke their covenant of Law that was given at Mount Sinai. They killed or ignored all the prophets that God repeatedly sent to them when they were separated into 2 kingdoms and went into captivity under Babylon, and then under Persia. (Matthew 21:33-46; Mark 12:1-12; Luke 20:9-19).
Thus, at the time of Jesus's first coming to Israel, many people in Israel are sick, demon possessed, precisely because they have forsaken that Law covenant. (Luke 13:11, Acts 3:2)
Jesus thus healed all of them to give them a taste of what life in that kingdom would be. Acts 10:38 is an especially beautiful summary by Peter to show that
How God anointed Jesus of Nazareth with the Holy Ghost and with power: who went about doing good, and healing all that were oppressed of the devil; for God was with him.
But now, God no longer relates to us under the Law (Romans 6:14, 1 Timothy 1:9).
So when we believers are sick nowadays, we can be rest assured that it is not because we have disobeyed God in anyway.
Conversely, if we find ourselves getting better, it is NOT because we are currently doing something that pleases God.
That is what I believe Paul is teaching us now when he shared with us Romans 8:18-25 and 2 Corinthians 4:16-18, and when he gave Timothy common sense advice regarding his frequent stomach aliments.